Large capacity rechargeable batteries are currently being investigated for use in electric vehicles. The ultimate feasibility of electric vehicles depends on significantly reducing the associated costs. Reduction in the costs of battery assemblies is particularly important.
Lithium-ion batteries are an important type of battery technology. Most battery assemblies, including lithium-ion battery assemblies, include a plurality of individual electrochemical cells. Typically, such electrochemical cells include an anode and a cathode. Typically, the anode includes a metal sheet or foil (usually copper metal) over-coated with a graphitic layer. Similarly, the cathode usually includes a metal sheet or foil (usually aluminum metal) over-coated with a lithium-containing layer. Finally, electrochemical cells include an electrolyte which is interposed between the anode and the cathode. Terminals allow the generated electricity to be used in an external circuit. Electrochemical cells produce electricity via an electrochemical reaction.
The increasing demand for improvements in lithium-ion batteries necessitates a complete understanding of the material in such cells as well as their changing compositions and performance overtime. Moreover, it is desired that such analytic techniques be inexpensive and easy to perform.
Accordingly, there is a need for improved techniques for evaluating compositional and functional changes in lithium-ion batteries.